Originally Posted by addictedtoplanes
I would like to keep it simple and cheap, would it work if I used a water bottle for the hull? Or are there any cheap sub kits out there? How easy would it be to convert a small plastic model kit, like 20"-25" long?
That is a dream for all of us, cheap and simple. I have seen WTCs (Water Tight Containers) made with simple devices and common materials. My Aluminaut is using less-expensive parts (ESC-Electronic Speed Controller for ~$7 US), the most expensive part is the receiver (~$40 US), but there are receivers out there for about ~$20 US - You get sometimes what you pay for.
Browse some of the works in progress at this site and others. You will see it can be done.